Mixed-order tangential vector finite elements for triangular elements

The paper begins by reviewing the principles of edge- and face-based vector basis functions for FEM expansion, using tangential vector finite elements (TVFEs) for triangular elements. A basic description of the hierarchical concept is then given and mixed-order TVFEs are described for triangular elements. After an introduction of the geometry, a presentation of the lowest-order TVFE (of order 0.5) is given. Subsequently, a non-hierarchical and a hierarchical TVFE of order 1.5 are presented.